diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/amplifiers/hmc425a.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/iio/amplifiers/hmc425a.c b/drivers/iio/amplifiers/hmc425a.c new file mode 100644 index 000000000..ce80e0c91 --- /dev/null +++ b/drivers/iio/amplifiers/hmc425a.c @@ -0,0 +1,244 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * HMC425A and similar Gain Amplifiers + * + * Copyright 2020 Analog Devices Inc. + */ + +#include <linux/device.h> +#include <linux/err.h> +#include <linux/gpio/consumer.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/kernel.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/slab.h> +#include <linux/regulator/consumer.h> +#include <linux/sysfs.h> + +enum hmc425a_type { + ID_HMC425A, +}; + +struct hmc425a_chip_info { + const char *name; + const struct iio_chan_spec *channels; + unsigned int num_channels; + unsigned int num_gpios; + int gain_min; + int gain_max; + int default_gain; +}; + +struct hmc425a_state { + struct regulator *reg; + struct mutex lock; /* protect sensor state */ + struct hmc425a_chip_info *chip_info; + struct gpio_descs *gpios; + enum hmc425a_type type; + u32 gain; +}; + +static int hmc425a_write(struct iio_dev *indio_dev, u32 value) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + DECLARE_BITMAP(values, BITS_PER_TYPE(value)); + + values[0] = value; + + gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc, + NULL, values); + return 0; +} + +static int hmc425a_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long m) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + int code, gain = 0; + int ret; + + mutex_lock(&st->lock); + switch (m) { + case IIO_CHAN_INFO_HARDWAREGAIN: + code = st->gain; + + switch (st->type) { + case ID_HMC425A: + gain = ~code * -500; + break; + } + + *val = gain / 1000; + *val2 = (gain % 1000) * 1000; + + ret = IIO_VAL_INT_PLUS_MICRO_DB; + break; + default: + ret = -EINVAL; + } + mutex_unlock(&st->lock); + + return ret; +}; + +static int hmc425a_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + struct hmc425a_state *st = iio_priv(indio_dev); + struct hmc425a_chip_info *inf = st->chip_info; + int code = 0, gain; + int ret; + + if (val < 0) + gain = (val * 1000) - (val2 / 1000); + else + gain = (val * 1000) + (val2 / 1000); + + if (gain > inf->gain_max || gain < inf->gain_min) + return -EINVAL; + + switch (st->type) { + case ID_HMC425A: + code = ~((abs(gain) / 500) & 0x3F); + break; + } + + mutex_lock(&st->lock); + switch (mask) { + case IIO_CHAN_INFO_HARDWAREGAIN: + st->gain = code; + + ret = hmc425a_write(indio_dev, st->gain); + break; + default: + ret = -EINVAL; + } + mutex_unlock(&st->lock); + + return ret; +} + +static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_HARDWAREGAIN: + return IIO_VAL_INT_PLUS_MICRO_DB; + default: + return -EINVAL; + } +} + +static const struct iio_info hmc425a_info = { + .read_raw = &hmc425a_read_raw, + .write_raw = &hmc425a_write_raw, + .write_raw_get_fmt = &hmc425a_write_raw_get_fmt, +}; + +#define HMC425A_CHAN(_channel) \ +{ \ + .type = IIO_VOLTAGE, \ + .output = 1, \ + .indexed = 1, \ + .channel = _channel, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ +} + +static const struct iio_chan_spec hmc425a_channels[] = { + HMC425A_CHAN(0), +}; + +/* Match table for of_platform binding */ +static const struct of_device_id hmc425a_of_match[] = { + { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A }, + {}, +}; +MODULE_DEVICE_TABLE(of, hmc425a_of_match); + +static void hmc425a_reg_disable(void *data) +{ + struct hmc425a_state *st = data; + + regulator_disable(st->reg); +} + +static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { + [ID_HMC425A] = { + .name = "hmc425a", + .channels = hmc425a_channels, + .num_channels = ARRAY_SIZE(hmc425a_channels), + .num_gpios = 6, + .gain_min = -31500, + .gain_max = 0, + .default_gain = -0x40, /* set default gain -31.5db*/ + }, +}; + +static int hmc425a_probe(struct platform_device *pdev) +{ + struct iio_dev *indio_dev; + struct hmc425a_state *st; + int ret; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); + if (!indio_dev) + return -ENOMEM; + + st = iio_priv(indio_dev); + st->type = (uintptr_t)device_get_match_data(&pdev->dev); + + st->chip_info = &hmc425a_chip_info_tbl[st->type]; + indio_dev->num_channels = st->chip_info->num_channels; + indio_dev->channels = st->chip_info->channels; + indio_dev->name = st->chip_info->name; + st->gain = st->chip_info->default_gain; + + st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW); + if (IS_ERR(st->gpios)) + return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios), + "failed to get gpios\n"); + + if (st->gpios->ndescs != st->chip_info->num_gpios) { + dev_err(&pdev->dev, "%d GPIOs needed to operate\n", + st->chip_info->num_gpios); + return -ENODEV; + } + + st->reg = devm_regulator_get(&pdev->dev, "vcc-supply"); + if (IS_ERR(st->reg)) + return PTR_ERR(st->reg); + + ret = regulator_enable(st->reg); + if (ret) + return ret; + ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st); + if (ret) + return ret; + + mutex_init(&st->lock); + + indio_dev->info = &hmc425a_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + return devm_iio_device_register(&pdev->dev, indio_dev); +} + +static struct platform_driver hmc425a_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = hmc425a_of_match, + }, + .probe = hmc425a_probe, +}; +module_platform_driver(hmc425a_driver); + +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); +MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers"); +MODULE_LICENSE("GPL v2"); |